If you don’t mind self hosting Mattermost is a pretty great replacement. Comes with some neat productivity tools and integrates with a lot of services including Microsoft stuff.

You can even have a bridge to Teams so you can set it up for the sort of nerds who appreciate full Markdown support with syntax highlighting.

To sell it to your boss, just say “If Teams is down, how will we get it working again?”

Here's the thing.... I work in IT and.... As much as many people don't want to hear it, Microsoft puts everything in one basket, and makes it easy to access and handle that basket.

You could go with gsuite/Google workspaces, and they have a lot of competing tools, like drive, meet, chat, Gmail, and their own office style suite.

Beyond that, you're going to start breaking up services between providers. Dropbox, email, zoom, etc... Each with their own logins per member of the team, increasing complexity exponentially.... Unless you can federate all your logins with someone, but the major players in business-ready, federated logins is.... Microsoft, Google, and companies like Ookla, of all people.

Which isn't to say anything about the compatibility issues with federation, and the complexity of setting it up when it works.

I struggled through trying to get federation working between a lot of different solutions and I'll just say, the whole thing is a nightmare, unless it's designed to go together from the start. You only get that if you go all in on one provider.... Like Microsoft 365.

People can say what they want, but Microsoft has taken their decades of experience making active directory, scaled it up to azure active directory (now entra ID), and built a full scale cloud service suite with everything fully integrated, and bluntly, simple to deploy by comparison. In the past, there were quite a few services, apps, programs, etc that directly interfaced with AD. Now that same functionality is a part of the foundations of entra.

My last company went to Zoom, funny enough, months before COVID hit and we all went WFH. I was the administrator and was thrilled with it. We used Google for identity management, clicked right in with some simple setup. Not sure how it plays with your MS ecosystem, but I'd bet money it's every bit as easy to tie your MS accounts to it.

We had a few clients and vendors that would suck us into Teams and Google meets and they fucking sucked. I honestly can't remember a single complaint I had with Zoom's software. Tech support was superb at the start, dropped drastically once they exploded in size with WFH and COVID. No idea how it stands now.

Google Chat is... acceptable. But its still invasive.

I always loved slack. Unless something changed in the past few years it's great.